1. Field of the Invention
The present invention relates to a radio wave receiver, and a method for producing a radio wave receiver.
2. Description of the Related Art
As a radio wave receiver, there has been known a radio-controlled timepiece which includes an antenna to receive a standard radio wave (standard time and frequency signal) containing time data inside the receiver, wherein the time is corrected based upon the standard radio wave received by the antenna.
In the case that such radio-controlled timepiece includes a case body and a rear case which are made of a metal, when the case body and the rear case are electrically connected to each other, an electric current circulating in the case body and the rear case increases, entailing a problem of a significant deterioration in the receiving sensitivity of the antenna. In view of this, a radio-controlled timepiece described below has been developed (e.g., see Japanese Patent Application Laid-Open Publication No. 2006-112866). Specifically, an insulating member or a spacer member having a large electrical resistance is provided between a metallic case body and a metallic rear case for avoiding a contact between the case body and the rear case. With this structure, an electric current circulating in the case body and the rear case is suppressed for preventing the deterioration in the receiving sensitivity of the antenna.
The metallic case body and the metallic rear case would be electrically connected to each other not only in the case where the case body and the rear case directly contact with each other, but also the case where the case body and the rear case are screwed with a metallic fixation screw. This is because the case body and the fixation screw are electrically connected and the fixation screw and the rear case are electrically connected, resulting in that the case body and the rear case might be electrically connected to each other.
In view of this, a radio-controlled wrist timepiece described below has recently been known (e.g., see Japanese Patent Application Laid-Open Publication No. 2008-82722). Specifically, an insulating member having a large electrical resistance is provided between a metallic case body and a metallic rear case, and a metallic fixation screw, on a surface of which an insulating member (insulating coat film) is formed, is used for fixing the rear case to the case body.
However, in the case of this radio-controlled timepiece, the fixation screw is rubbed with the case body and the rear case when the fixation screw is fastened, so that the insulating coat film formed on the fixation screw might be destroyed. As a result, the case body and the rear case might become electrically conductive through the destroyed portion of the insulating coat film on the fixation screw.